Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/kernel/fork.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * 'fork.c' contains the help-routines for the 'fork' system call | |
9 | * (see also entry.S and others). | |
10 | * Fork is rather simple, once you get the hang of it, but the memory | |
11 | * management can be a bitch. See 'mm/memory.c': 'copy_page_range()' | |
12 | */ | |
13 | ||
1da177e4 LT |
14 | #include <linux/slab.h> |
15 | #include <linux/init.h> | |
16 | #include <linux/unistd.h> | |
1da177e4 LT |
17 | #include <linux/module.h> |
18 | #include <linux/vmalloc.h> | |
19 | #include <linux/completion.h> | |
1da177e4 LT |
20 | #include <linux/personality.h> |
21 | #include <linux/mempolicy.h> | |
22 | #include <linux/sem.h> | |
23 | #include <linux/file.h> | |
9f3acc31 | 24 | #include <linux/fdtable.h> |
da9cbc87 | 25 | #include <linux/iocontext.h> |
1da177e4 LT |
26 | #include <linux/key.h> |
27 | #include <linux/binfmts.h> | |
28 | #include <linux/mman.h> | |
cddb8a5c | 29 | #include <linux/mmu_notifier.h> |
1da177e4 | 30 | #include <linux/fs.h> |
ab516013 | 31 | #include <linux/nsproxy.h> |
c59ede7b | 32 | #include <linux/capability.h> |
1da177e4 | 33 | #include <linux/cpu.h> |
b4f48b63 | 34 | #include <linux/cgroup.h> |
1da177e4 | 35 | #include <linux/security.h> |
a1e78772 | 36 | #include <linux/hugetlb.h> |
1da177e4 LT |
37 | #include <linux/swap.h> |
38 | #include <linux/syscalls.h> | |
39 | #include <linux/jiffies.h> | |
09a05394 | 40 | #include <linux/tracehook.h> |
1da177e4 | 41 | #include <linux/futex.h> |
8141c7f3 | 42 | #include <linux/compat.h> |
7c3ab738 | 43 | #include <linux/task_io_accounting_ops.h> |
ab2af1f5 | 44 | #include <linux/rcupdate.h> |
1da177e4 LT |
45 | #include <linux/ptrace.h> |
46 | #include <linux/mount.h> | |
47 | #include <linux/audit.h> | |
78fb7466 | 48 | #include <linux/memcontrol.h> |
f201ae23 | 49 | #include <linux/ftrace.h> |
1da177e4 LT |
50 | #include <linux/profile.h> |
51 | #include <linux/rmap.h> | |
f8af4da3 | 52 | #include <linux/ksm.h> |
1da177e4 | 53 | #include <linux/acct.h> |
8f0ab514 | 54 | #include <linux/tsacct_kern.h> |
9f46080c | 55 | #include <linux/cn_proc.h> |
ba96a0c8 | 56 | #include <linux/freezer.h> |
ca74e92b | 57 | #include <linux/delayacct.h> |
ad4ecbcb | 58 | #include <linux/taskstats_kern.h> |
0a425405 | 59 | #include <linux/random.h> |
522ed776 | 60 | #include <linux/tty.h> |
6f4e6433 | 61 | #include <linux/proc_fs.h> |
fd0928df | 62 | #include <linux/blkdev.h> |
5ad4e53b | 63 | #include <linux/fs_struct.h> |
7c9f8861 | 64 | #include <linux/magic.h> |
cdd6c482 | 65 | #include <linux/perf_event.h> |
42c4ab41 | 66 | #include <linux/posix-timers.h> |
8e7cac79 | 67 | #include <linux/user-return-notifier.h> |
3d5992d2 | 68 | #include <linux/oom.h> |
ba76149f | 69 | #include <linux/khugepaged.h> |
1da177e4 LT |
70 | |
71 | #include <asm/pgtable.h> | |
72 | #include <asm/pgalloc.h> | |
73 | #include <asm/uaccess.h> | |
74 | #include <asm/mmu_context.h> | |
75 | #include <asm/cacheflush.h> | |
76 | #include <asm/tlbflush.h> | |
77 | ||
ad8d75ff SR |
78 | #include <trace/events/sched.h> |
79 | ||
1da177e4 LT |
80 | /* |
81 | * Protected counters by write_lock_irq(&tasklist_lock) | |
82 | */ | |
83 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
84 | int nr_threads; /* The idle threads do not count.. */ | |
85 | ||
86 | int max_threads; /* tunable limit on nr_threads */ | |
87 | ||
88 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
89 | ||
c59923a1 | 90 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
db1466b3 PM |
91 | |
92 | #ifdef CONFIG_PROVE_RCU | |
93 | int lockdep_tasklist_lock_is_held(void) | |
94 | { | |
95 | return lockdep_is_held(&tasklist_lock); | |
96 | } | |
97 | EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held); | |
98 | #endif /* #ifdef CONFIG_PROVE_RCU */ | |
1da177e4 LT |
99 | |
100 | int nr_processes(void) | |
101 | { | |
102 | int cpu; | |
103 | int total = 0; | |
104 | ||
1d510750 | 105 | for_each_possible_cpu(cpu) |
1da177e4 LT |
106 | total += per_cpu(process_counts, cpu); |
107 | ||
108 | return total; | |
109 | } | |
110 | ||
111 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
504f52b5 ED |
112 | # define alloc_task_struct_node(node) \ |
113 | kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node) | |
114 | # define free_task_struct(tsk) \ | |
115 | kmem_cache_free(task_struct_cachep, (tsk)) | |
e18b890b | 116 | static struct kmem_cache *task_struct_cachep; |
1da177e4 LT |
117 | #endif |
118 | ||
b69c49b7 FT |
119 | #ifndef __HAVE_ARCH_THREAD_INFO_ALLOCATOR |
120 | static inline struct thread_info *alloc_thread_info(struct task_struct *tsk) | |
121 | { | |
122 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
123 | gfp_t mask = GFP_KERNEL | __GFP_ZERO; | |
124 | #else | |
125 | gfp_t mask = GFP_KERNEL; | |
126 | #endif | |
127 | return (struct thread_info *)__get_free_pages(mask, THREAD_SIZE_ORDER); | |
128 | } | |
129 | ||
130 | static inline void free_thread_info(struct thread_info *ti) | |
131 | { | |
132 | free_pages((unsigned long)ti, THREAD_SIZE_ORDER); | |
133 | } | |
134 | #endif | |
135 | ||
1da177e4 | 136 | /* SLAB cache for signal_struct structures (tsk->signal) */ |
e18b890b | 137 | static struct kmem_cache *signal_cachep; |
1da177e4 LT |
138 | |
139 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
e18b890b | 140 | struct kmem_cache *sighand_cachep; |
1da177e4 LT |
141 | |
142 | /* SLAB cache for files_struct structures (tsk->files) */ | |
e18b890b | 143 | struct kmem_cache *files_cachep; |
1da177e4 LT |
144 | |
145 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
e18b890b | 146 | struct kmem_cache *fs_cachep; |
1da177e4 LT |
147 | |
148 | /* SLAB cache for vm_area_struct structures */ | |
e18b890b | 149 | struct kmem_cache *vm_area_cachep; |
1da177e4 LT |
150 | |
151 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
e18b890b | 152 | static struct kmem_cache *mm_cachep; |
1da177e4 | 153 | |
c6a7f572 KM |
154 | static void account_kernel_stack(struct thread_info *ti, int account) |
155 | { | |
156 | struct zone *zone = page_zone(virt_to_page(ti)); | |
157 | ||
158 | mod_zone_page_state(zone, NR_KERNEL_STACK, account); | |
159 | } | |
160 | ||
1da177e4 LT |
161 | void free_task(struct task_struct *tsk) |
162 | { | |
3e26c149 | 163 | prop_local_destroy_single(&tsk->dirties); |
c6a7f572 | 164 | account_kernel_stack(tsk->stack, -1); |
f7e4217b | 165 | free_thread_info(tsk->stack); |
23f78d4a | 166 | rt_mutex_debug_task_free(tsk); |
fb52607a | 167 | ftrace_graph_exit_task(tsk); |
1da177e4 LT |
168 | free_task_struct(tsk); |
169 | } | |
170 | EXPORT_SYMBOL(free_task); | |
171 | ||
ea6d290c ON |
172 | static inline void free_signal_struct(struct signal_struct *sig) |
173 | { | |
97101eb4 | 174 | taskstats_tgid_free(sig); |
1c5354de | 175 | sched_autogroup_exit(sig); |
ea6d290c ON |
176 | kmem_cache_free(signal_cachep, sig); |
177 | } | |
178 | ||
179 | static inline void put_signal_struct(struct signal_struct *sig) | |
180 | { | |
1c5354de | 181 | if (atomic_dec_and_test(&sig->sigcnt)) |
ea6d290c ON |
182 | free_signal_struct(sig); |
183 | } | |
184 | ||
158d9ebd | 185 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 | 186 | { |
270f722d | 187 | WARN_ON(!tsk->exit_state); |
1da177e4 LT |
188 | WARN_ON(atomic_read(&tsk->usage)); |
189 | WARN_ON(tsk == current); | |
190 | ||
e0e81739 | 191 | exit_creds(tsk); |
35df17c5 | 192 | delayacct_tsk_free(tsk); |
ea6d290c | 193 | put_signal_struct(tsk->signal); |
1da177e4 LT |
194 | |
195 | if (!profile_handoff_task(tsk)) | |
196 | free_task(tsk); | |
197 | } | |
77c100c8 | 198 | EXPORT_SYMBOL_GPL(__put_task_struct); |
1da177e4 | 199 | |
2adee9b3 SS |
200 | /* |
201 | * macro override instead of weak attribute alias, to workaround | |
202 | * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions. | |
203 | */ | |
204 | #ifndef arch_task_cache_init | |
205 | #define arch_task_cache_init() | |
206 | #endif | |
61c4628b | 207 | |
1da177e4 LT |
208 | void __init fork_init(unsigned long mempages) |
209 | { | |
210 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
211 | #ifndef ARCH_MIN_TASKALIGN | |
212 | #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES | |
213 | #endif | |
214 | /* create a slab on which task_structs can be allocated */ | |
215 | task_struct_cachep = | |
216 | kmem_cache_create("task_struct", sizeof(struct task_struct), | |
2dff4405 | 217 | ARCH_MIN_TASKALIGN, SLAB_PANIC | SLAB_NOTRACK, NULL); |
1da177e4 LT |
218 | #endif |
219 | ||
61c4628b SS |
220 | /* do the arch specific task caches init */ |
221 | arch_task_cache_init(); | |
222 | ||
1da177e4 LT |
223 | /* |
224 | * The default maximum number of threads is set to a safe | |
225 | * value: the thread structures can take up at most half | |
226 | * of memory. | |
227 | */ | |
228 | max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); | |
229 | ||
230 | /* | |
231 | * we need to allow at least 20 threads to boot a system | |
232 | */ | |
233 | if(max_threads < 20) | |
234 | max_threads = 20; | |
235 | ||
236 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
237 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
238 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
239 | init_task.signal->rlim[RLIMIT_NPROC]; | |
240 | } | |
241 | ||
61c4628b SS |
242 | int __attribute__((weak)) arch_dup_task_struct(struct task_struct *dst, |
243 | struct task_struct *src) | |
244 | { | |
245 | *dst = *src; | |
246 | return 0; | |
247 | } | |
248 | ||
1da177e4 LT |
249 | static struct task_struct *dup_task_struct(struct task_struct *orig) |
250 | { | |
251 | struct task_struct *tsk; | |
252 | struct thread_info *ti; | |
7c9f8861 | 253 | unsigned long *stackend; |
504f52b5 | 254 | int node = numa_node_id(); |
3e26c149 | 255 | int err; |
1da177e4 LT |
256 | |
257 | prepare_to_copy(orig); | |
258 | ||
504f52b5 | 259 | tsk = alloc_task_struct_node(node); |
1da177e4 LT |
260 | if (!tsk) |
261 | return NULL; | |
262 | ||
263 | ti = alloc_thread_info(tsk); | |
264 | if (!ti) { | |
265 | free_task_struct(tsk); | |
266 | return NULL; | |
267 | } | |
268 | ||
61c4628b SS |
269 | err = arch_dup_task_struct(tsk, orig); |
270 | if (err) | |
271 | goto out; | |
272 | ||
f7e4217b | 273 | tsk->stack = ti; |
3e26c149 PZ |
274 | |
275 | err = prop_local_init_single(&tsk->dirties); | |
61c4628b SS |
276 | if (err) |
277 | goto out; | |
3e26c149 | 278 | |
10ebffde | 279 | setup_thread_stack(tsk, orig); |
8e7cac79 | 280 | clear_user_return_notifier(tsk); |
f26f9aff | 281 | clear_tsk_need_resched(tsk); |
7c9f8861 ES |
282 | stackend = end_of_stack(tsk); |
283 | *stackend = STACK_END_MAGIC; /* for overflow detection */ | |
1da177e4 | 284 | |
0a425405 AV |
285 | #ifdef CONFIG_CC_STACKPROTECTOR |
286 | tsk->stack_canary = get_random_int(); | |
287 | #endif | |
288 | ||
1da177e4 LT |
289 | /* One for us, one for whoever does the "release_task()" (usually parent) */ |
290 | atomic_set(&tsk->usage,2); | |
4b5d37ac | 291 | atomic_set(&tsk->fs_excl, 0); |
6c5c9341 | 292 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 293 | tsk->btrace_seq = 0; |
6c5c9341 | 294 | #endif |
a0aa7f68 | 295 | tsk->splice_pipe = NULL; |
c6a7f572 KM |
296 | |
297 | account_kernel_stack(ti, 1); | |
298 | ||
1da177e4 | 299 | return tsk; |
61c4628b SS |
300 | |
301 | out: | |
302 | free_thread_info(ti); | |
303 | free_task_struct(tsk); | |
304 | return NULL; | |
1da177e4 LT |
305 | } |
306 | ||
307 | #ifdef CONFIG_MMU | |
a39bc516 | 308 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
1da177e4 | 309 | { |
297c5eee | 310 | struct vm_area_struct *mpnt, *tmp, *prev, **pprev; |
1da177e4 LT |
311 | struct rb_node **rb_link, *rb_parent; |
312 | int retval; | |
313 | unsigned long charge; | |
314 | struct mempolicy *pol; | |
315 | ||
316 | down_write(&oldmm->mmap_sem); | |
ec8c0446 | 317 | flush_cache_dup_mm(oldmm); |
ad339451 IM |
318 | /* |
319 | * Not linked in yet - no deadlock potential: | |
320 | */ | |
321 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); | |
7ee78232 | 322 | |
1da177e4 LT |
323 | mm->locked_vm = 0; |
324 | mm->mmap = NULL; | |
325 | mm->mmap_cache = NULL; | |
326 | mm->free_area_cache = oldmm->mmap_base; | |
1363c3cd | 327 | mm->cached_hole_size = ~0UL; |
1da177e4 | 328 | mm->map_count = 0; |
94894244 | 329 | cpumask_clear(mm_cpumask(mm)); |
1da177e4 LT |
330 | mm->mm_rb = RB_ROOT; |
331 | rb_link = &mm->mm_rb.rb_node; | |
332 | rb_parent = NULL; | |
333 | pprev = &mm->mmap; | |
f8af4da3 | 334 | retval = ksm_fork(mm, oldmm); |
ba76149f AA |
335 | if (retval) |
336 | goto out; | |
337 | retval = khugepaged_fork(mm, oldmm); | |
f8af4da3 HD |
338 | if (retval) |
339 | goto out; | |
1da177e4 | 340 | |
297c5eee | 341 | prev = NULL; |
fd3e42fc | 342 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
1da177e4 LT |
343 | struct file *file; |
344 | ||
345 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
3b6bfcdb HD |
346 | long pages = vma_pages(mpnt); |
347 | mm->total_vm -= pages; | |
ab50b8ed | 348 | vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, |
3b6bfcdb | 349 | -pages); |
1da177e4 LT |
350 | continue; |
351 | } | |
352 | charge = 0; | |
353 | if (mpnt->vm_flags & VM_ACCOUNT) { | |
354 | unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; | |
355 | if (security_vm_enough_memory(len)) | |
356 | goto fail_nomem; | |
357 | charge = len; | |
358 | } | |
e94b1766 | 359 | tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
360 | if (!tmp) |
361 | goto fail_nomem; | |
362 | *tmp = *mpnt; | |
5beb4930 | 363 | INIT_LIST_HEAD(&tmp->anon_vma_chain); |
846a16bf | 364 | pol = mpol_dup(vma_policy(mpnt)); |
1da177e4 LT |
365 | retval = PTR_ERR(pol); |
366 | if (IS_ERR(pol)) | |
367 | goto fail_nomem_policy; | |
368 | vma_set_policy(tmp, pol); | |
a247c3a9 | 369 | tmp->vm_mm = mm; |
5beb4930 RR |
370 | if (anon_vma_fork(tmp, mpnt)) |
371 | goto fail_nomem_anon_vma_fork; | |
1da177e4 | 372 | tmp->vm_flags &= ~VM_LOCKED; |
297c5eee | 373 | tmp->vm_next = tmp->vm_prev = NULL; |
1da177e4 LT |
374 | file = tmp->vm_file; |
375 | if (file) { | |
f3a43f3f | 376 | struct inode *inode = file->f_path.dentry->d_inode; |
b88ed205 HD |
377 | struct address_space *mapping = file->f_mapping; |
378 | ||
1da177e4 LT |
379 | get_file(file); |
380 | if (tmp->vm_flags & VM_DENYWRITE) | |
381 | atomic_dec(&inode->i_writecount); | |
b88ed205 HD |
382 | spin_lock(&mapping->i_mmap_lock); |
383 | if (tmp->vm_flags & VM_SHARED) | |
384 | mapping->i_mmap_writable++; | |
1da177e4 | 385 | tmp->vm_truncate_count = mpnt->vm_truncate_count; |
b88ed205 HD |
386 | flush_dcache_mmap_lock(mapping); |
387 | /* insert tmp into the share list, just after mpnt */ | |
1da177e4 | 388 | vma_prio_tree_add(tmp, mpnt); |
b88ed205 HD |
389 | flush_dcache_mmap_unlock(mapping); |
390 | spin_unlock(&mapping->i_mmap_lock); | |
1da177e4 LT |
391 | } |
392 | ||
a1e78772 MG |
393 | /* |
394 | * Clear hugetlb-related page reserves for children. This only | |
395 | * affects MAP_PRIVATE mappings. Faults generated by the child | |
396 | * are not guaranteed to succeed, even if read-only | |
397 | */ | |
398 | if (is_vm_hugetlb_page(tmp)) | |
399 | reset_vma_resv_huge_pages(tmp); | |
400 | ||
1da177e4 | 401 | /* |
7ee78232 | 402 | * Link in the new vma and copy the page table entries. |
1da177e4 | 403 | */ |
1da177e4 LT |
404 | *pprev = tmp; |
405 | pprev = &tmp->vm_next; | |
297c5eee LT |
406 | tmp->vm_prev = prev; |
407 | prev = tmp; | |
1da177e4 LT |
408 | |
409 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
410 | rb_link = &tmp->vm_rb.rb_right; | |
411 | rb_parent = &tmp->vm_rb; | |
412 | ||
413 | mm->map_count++; | |
0b0db14c | 414 | retval = copy_page_range(mm, oldmm, mpnt); |
1da177e4 LT |
415 | |
416 | if (tmp->vm_ops && tmp->vm_ops->open) | |
417 | tmp->vm_ops->open(tmp); | |
418 | ||
419 | if (retval) | |
420 | goto out; | |
421 | } | |
d6dd61c8 JF |
422 | /* a new mm has just been created */ |
423 | arch_dup_mmap(oldmm, mm); | |
1da177e4 | 424 | retval = 0; |
1da177e4 | 425 | out: |
7ee78232 | 426 | up_write(&mm->mmap_sem); |
fd3e42fc | 427 | flush_tlb_mm(oldmm); |
1da177e4 LT |
428 | up_write(&oldmm->mmap_sem); |
429 | return retval; | |
5beb4930 RR |
430 | fail_nomem_anon_vma_fork: |
431 | mpol_put(pol); | |
1da177e4 LT |
432 | fail_nomem_policy: |
433 | kmem_cache_free(vm_area_cachep, tmp); | |
434 | fail_nomem: | |
435 | retval = -ENOMEM; | |
436 | vm_unacct_memory(charge); | |
437 | goto out; | |
438 | } | |
439 | ||
440 | static inline int mm_alloc_pgd(struct mm_struct * mm) | |
441 | { | |
442 | mm->pgd = pgd_alloc(mm); | |
443 | if (unlikely(!mm->pgd)) | |
444 | return -ENOMEM; | |
445 | return 0; | |
446 | } | |
447 | ||
448 | static inline void mm_free_pgd(struct mm_struct * mm) | |
449 | { | |
5e541973 | 450 | pgd_free(mm, mm->pgd); |
1da177e4 LT |
451 | } |
452 | #else | |
453 | #define dup_mmap(mm, oldmm) (0) | |
454 | #define mm_alloc_pgd(mm) (0) | |
455 | #define mm_free_pgd(mm) | |
456 | #endif /* CONFIG_MMU */ | |
457 | ||
23ff4440 | 458 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
1da177e4 | 459 | |
e94b1766 | 460 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) |
1da177e4 LT |
461 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) |
462 | ||
4cb0e11b HK |
463 | static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT; |
464 | ||
465 | static int __init coredump_filter_setup(char *s) | |
466 | { | |
467 | default_dump_filter = | |
468 | (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) & | |
469 | MMF_DUMP_FILTER_MASK; | |
470 | return 1; | |
471 | } | |
472 | ||
473 | __setup("coredump_filter=", coredump_filter_setup); | |
474 | ||
1da177e4 LT |
475 | #include <linux/init_task.h> |
476 | ||
858f0993 AD |
477 | static void mm_init_aio(struct mm_struct *mm) |
478 | { | |
479 | #ifdef CONFIG_AIO | |
480 | spin_lock_init(&mm->ioctx_lock); | |
481 | INIT_HLIST_HEAD(&mm->ioctx_list); | |
482 | #endif | |
483 | } | |
484 | ||
78fb7466 | 485 | static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p) |
1da177e4 LT |
486 | { |
487 | atomic_set(&mm->mm_users, 1); | |
488 | atomic_set(&mm->mm_count, 1); | |
489 | init_rwsem(&mm->mmap_sem); | |
490 | INIT_LIST_HEAD(&mm->mmlist); | |
f8af4da3 HD |
491 | mm->flags = (current->mm) ? |
492 | (current->mm->flags & MMF_INIT_MASK) : default_dump_filter; | |
999d9fc1 | 493 | mm->core_state = NULL; |
1da177e4 | 494 | mm->nr_ptes = 0; |
d559db08 | 495 | memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); |
1da177e4 | 496 | spin_lock_init(&mm->page_table_lock); |
1da177e4 | 497 | mm->free_area_cache = TASK_UNMAPPED_BASE; |
1363c3cd | 498 | mm->cached_hole_size = ~0UL; |
858f0993 | 499 | mm_init_aio(mm); |
cf475ad2 | 500 | mm_init_owner(mm, p); |
3d5992d2 | 501 | atomic_set(&mm->oom_disable_count, 0); |
1da177e4 LT |
502 | |
503 | if (likely(!mm_alloc_pgd(mm))) { | |
504 | mm->def_flags = 0; | |
cddb8a5c | 505 | mmu_notifier_mm_init(mm); |
1da177e4 LT |
506 | return mm; |
507 | } | |
78fb7466 | 508 | |
1da177e4 LT |
509 | free_mm(mm); |
510 | return NULL; | |
511 | } | |
512 | ||
513 | /* | |
514 | * Allocate and initialize an mm_struct. | |
515 | */ | |
516 | struct mm_struct * mm_alloc(void) | |
517 | { | |
518 | struct mm_struct * mm; | |
519 | ||
520 | mm = allocate_mm(); | |
521 | if (mm) { | |
522 | memset(mm, 0, sizeof(*mm)); | |
78fb7466 | 523 | mm = mm_init(mm, current); |
1da177e4 LT |
524 | } |
525 | return mm; | |
526 | } | |
527 | ||
528 | /* | |
529 | * Called when the last reference to the mm | |
530 | * is dropped: either by a lazy thread or by | |
531 | * mmput. Free the page directory and the mm. | |
532 | */ | |
7ad5b3a5 | 533 | void __mmdrop(struct mm_struct *mm) |
1da177e4 LT |
534 | { |
535 | BUG_ON(mm == &init_mm); | |
536 | mm_free_pgd(mm); | |
537 | destroy_context(mm); | |
cddb8a5c | 538 | mmu_notifier_mm_destroy(mm); |
e7a00c45 AA |
539 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
540 | VM_BUG_ON(mm->pmd_huge_pte); | |
541 | #endif | |
1da177e4 LT |
542 | free_mm(mm); |
543 | } | |
6d4e4c4f | 544 | EXPORT_SYMBOL_GPL(__mmdrop); |
1da177e4 LT |
545 | |
546 | /* | |
547 | * Decrement the use count and release all resources for an mm. | |
548 | */ | |
549 | void mmput(struct mm_struct *mm) | |
550 | { | |
0ae26f1b AM |
551 | might_sleep(); |
552 | ||
1da177e4 LT |
553 | if (atomic_dec_and_test(&mm->mm_users)) { |
554 | exit_aio(mm); | |
1c2fb7a4 | 555 | ksm_exit(mm); |
ba76149f | 556 | khugepaged_exit(mm); /* must run before exit_mmap */ |
1da177e4 | 557 | exit_mmap(mm); |
925d1c40 | 558 | set_mm_exe_file(mm, NULL); |
1da177e4 LT |
559 | if (!list_empty(&mm->mmlist)) { |
560 | spin_lock(&mmlist_lock); | |
561 | list_del(&mm->mmlist); | |
562 | spin_unlock(&mmlist_lock); | |
563 | } | |
564 | put_swap_token(mm); | |
801460d0 HS |
565 | if (mm->binfmt) |
566 | module_put(mm->binfmt->module); | |
1da177e4 LT |
567 | mmdrop(mm); |
568 | } | |
569 | } | |
570 | EXPORT_SYMBOL_GPL(mmput); | |
571 | ||
572 | /** | |
573 | * get_task_mm - acquire a reference to the task's mm | |
574 | * | |
246bb0b1 | 575 | * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning |
1da177e4 LT |
576 | * this kernel workthread has transiently adopted a user mm with use_mm, |
577 | * to do its AIO) is not set and if so returns a reference to it, after | |
578 | * bumping up the use count. User must release the mm via mmput() | |
579 | * after use. Typically used by /proc and ptrace. | |
580 | */ | |
581 | struct mm_struct *get_task_mm(struct task_struct *task) | |
582 | { | |
583 | struct mm_struct *mm; | |
584 | ||
585 | task_lock(task); | |
586 | mm = task->mm; | |
587 | if (mm) { | |
246bb0b1 | 588 | if (task->flags & PF_KTHREAD) |
1da177e4 LT |
589 | mm = NULL; |
590 | else | |
591 | atomic_inc(&mm->mm_users); | |
592 | } | |
593 | task_unlock(task); | |
594 | return mm; | |
595 | } | |
596 | EXPORT_SYMBOL_GPL(get_task_mm); | |
597 | ||
598 | /* Please note the differences between mmput and mm_release. | |
599 | * mmput is called whenever we stop holding onto a mm_struct, | |
600 | * error success whatever. | |
601 | * | |
602 | * mm_release is called after a mm_struct has been removed | |
603 | * from the current process. | |
604 | * | |
605 | * This difference is important for error handling, when we | |
606 | * only half set up a mm_struct for a new process and need to restore | |
607 | * the old one. Because we mmput the new mm_struct before | |
608 | * restoring the old one. . . | |
609 | * Eric Biederman 10 January 1998 | |
610 | */ | |
611 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
612 | { | |
613 | struct completion *vfork_done = tsk->vfork_done; | |
614 | ||
8141c7f3 LT |
615 | /* Get rid of any futexes when releasing the mm */ |
616 | #ifdef CONFIG_FUTEX | |
fc6b177d | 617 | if (unlikely(tsk->robust_list)) { |
8141c7f3 | 618 | exit_robust_list(tsk); |
fc6b177d PZ |
619 | tsk->robust_list = NULL; |
620 | } | |
8141c7f3 | 621 | #ifdef CONFIG_COMPAT |
fc6b177d | 622 | if (unlikely(tsk->compat_robust_list)) { |
8141c7f3 | 623 | compat_exit_robust_list(tsk); |
fc6b177d PZ |
624 | tsk->compat_robust_list = NULL; |
625 | } | |
8141c7f3 | 626 | #endif |
322a2c10 TG |
627 | if (unlikely(!list_empty(&tsk->pi_state_list))) |
628 | exit_pi_state_list(tsk); | |
8141c7f3 LT |
629 | #endif |
630 | ||
1da177e4 LT |
631 | /* Get rid of any cached register state */ |
632 | deactivate_mm(tsk, mm); | |
633 | ||
634 | /* notify parent sleeping on vfork() */ | |
635 | if (vfork_done) { | |
636 | tsk->vfork_done = NULL; | |
637 | complete(vfork_done); | |
638 | } | |
fec1d011 RM |
639 | |
640 | /* | |
641 | * If we're exiting normally, clear a user-space tid field if | |
642 | * requested. We leave this alone when dying by signal, to leave | |
643 | * the value intact in a core dump, and to save the unnecessary | |
644 | * trouble otherwise. Userland only wants this done for a sys_exit. | |
645 | */ | |
9c8a8228 ED |
646 | if (tsk->clear_child_tid) { |
647 | if (!(tsk->flags & PF_SIGNALED) && | |
648 | atomic_read(&mm->mm_users) > 1) { | |
649 | /* | |
650 | * We don't check the error code - if userspace has | |
651 | * not set up a proper pointer then tough luck. | |
652 | */ | |
653 | put_user(0, tsk->clear_child_tid); | |
654 | sys_futex(tsk->clear_child_tid, FUTEX_WAKE, | |
655 | 1, NULL, NULL, 0); | |
656 | } | |
1da177e4 | 657 | tsk->clear_child_tid = NULL; |
1da177e4 LT |
658 | } |
659 | } | |
660 | ||
a0a7ec30 JD |
661 | /* |
662 | * Allocate a new mm structure and copy contents from the | |
663 | * mm structure of the passed in task structure. | |
664 | */ | |
402b0862 | 665 | struct mm_struct *dup_mm(struct task_struct *tsk) |
a0a7ec30 JD |
666 | { |
667 | struct mm_struct *mm, *oldmm = current->mm; | |
668 | int err; | |
669 | ||
670 | if (!oldmm) | |
671 | return NULL; | |
672 | ||
673 | mm = allocate_mm(); | |
674 | if (!mm) | |
675 | goto fail_nomem; | |
676 | ||
677 | memcpy(mm, oldmm, sizeof(*mm)); | |
678 | ||
7602bdf2 AC |
679 | /* Initializing for Swap token stuff */ |
680 | mm->token_priority = 0; | |
681 | mm->last_interval = 0; | |
682 | ||
e7a00c45 AA |
683 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
684 | mm->pmd_huge_pte = NULL; | |
685 | #endif | |
686 | ||
78fb7466 | 687 | if (!mm_init(mm, tsk)) |
a0a7ec30 JD |
688 | goto fail_nomem; |
689 | ||
690 | if (init_new_context(tsk, mm)) | |
691 | goto fail_nocontext; | |
692 | ||
925d1c40 MH |
693 | dup_mm_exe_file(oldmm, mm); |
694 | ||
a0a7ec30 JD |
695 | err = dup_mmap(mm, oldmm); |
696 | if (err) | |
697 | goto free_pt; | |
698 | ||
699 | mm->hiwater_rss = get_mm_rss(mm); | |
700 | mm->hiwater_vm = mm->total_vm; | |
701 | ||
801460d0 HS |
702 | if (mm->binfmt && !try_module_get(mm->binfmt->module)) |
703 | goto free_pt; | |
704 | ||
a0a7ec30 JD |
705 | return mm; |
706 | ||
707 | free_pt: | |
801460d0 HS |
708 | /* don't put binfmt in mmput, we haven't got module yet */ |
709 | mm->binfmt = NULL; | |
a0a7ec30 JD |
710 | mmput(mm); |
711 | ||
712 | fail_nomem: | |
713 | return NULL; | |
714 | ||
715 | fail_nocontext: | |
716 | /* | |
717 | * If init_new_context() failed, we cannot use mmput() to free the mm | |
718 | * because it calls destroy_context() | |
719 | */ | |
720 | mm_free_pgd(mm); | |
721 | free_mm(mm); | |
722 | return NULL; | |
723 | } | |
724 | ||
1da177e4 LT |
725 | static int copy_mm(unsigned long clone_flags, struct task_struct * tsk) |
726 | { | |
727 | struct mm_struct * mm, *oldmm; | |
728 | int retval; | |
729 | ||
730 | tsk->min_flt = tsk->maj_flt = 0; | |
731 | tsk->nvcsw = tsk->nivcsw = 0; | |
17406b82 MSB |
732 | #ifdef CONFIG_DETECT_HUNG_TASK |
733 | tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw; | |
734 | #endif | |
1da177e4 LT |
735 | |
736 | tsk->mm = NULL; | |
737 | tsk->active_mm = NULL; | |
738 | ||
739 | /* | |
740 | * Are we cloning a kernel thread? | |
741 | * | |
742 | * We need to steal a active VM for that.. | |
743 | */ | |
744 | oldmm = current->mm; | |
745 | if (!oldmm) | |
746 | return 0; | |
747 | ||
748 | if (clone_flags & CLONE_VM) { | |
749 | atomic_inc(&oldmm->mm_users); | |
750 | mm = oldmm; | |
1da177e4 LT |
751 | goto good_mm; |
752 | } | |
753 | ||
754 | retval = -ENOMEM; | |
a0a7ec30 | 755 | mm = dup_mm(tsk); |
1da177e4 LT |
756 | if (!mm) |
757 | goto fail_nomem; | |
758 | ||
1da177e4 | 759 | good_mm: |
7602bdf2 AC |
760 | /* Initializing for Swap token stuff */ |
761 | mm->token_priority = 0; | |
762 | mm->last_interval = 0; | |
3d5992d2 YH |
763 | if (tsk->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) |
764 | atomic_inc(&mm->oom_disable_count); | |
7602bdf2 | 765 | |
1da177e4 LT |
766 | tsk->mm = mm; |
767 | tsk->active_mm = mm; | |
768 | return 0; | |
769 | ||
1da177e4 LT |
770 | fail_nomem: |
771 | return retval; | |
1da177e4 LT |
772 | } |
773 | ||
a39bc516 | 774 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 775 | { |
498052bb | 776 | struct fs_struct *fs = current->fs; |
1da177e4 | 777 | if (clone_flags & CLONE_FS) { |
498052bb | 778 | /* tsk->fs is already what we want */ |
2a4419b5 | 779 | spin_lock(&fs->lock); |
498052bb | 780 | if (fs->in_exec) { |
2a4419b5 | 781 | spin_unlock(&fs->lock); |
498052bb AV |
782 | return -EAGAIN; |
783 | } | |
784 | fs->users++; | |
2a4419b5 | 785 | spin_unlock(&fs->lock); |
1da177e4 LT |
786 | return 0; |
787 | } | |
498052bb | 788 | tsk->fs = copy_fs_struct(fs); |
1da177e4 LT |
789 | if (!tsk->fs) |
790 | return -ENOMEM; | |
791 | return 0; | |
792 | } | |
793 | ||
a016f338 JD |
794 | static int copy_files(unsigned long clone_flags, struct task_struct * tsk) |
795 | { | |
796 | struct files_struct *oldf, *newf; | |
797 | int error = 0; | |
798 | ||
799 | /* | |
800 | * A background process may not have any files ... | |
801 | */ | |
802 | oldf = current->files; | |
803 | if (!oldf) | |
804 | goto out; | |
805 | ||
806 | if (clone_flags & CLONE_FILES) { | |
807 | atomic_inc(&oldf->count); | |
808 | goto out; | |
809 | } | |
810 | ||
a016f338 JD |
811 | newf = dup_fd(oldf, &error); |
812 | if (!newf) | |
813 | goto out; | |
814 | ||
815 | tsk->files = newf; | |
816 | error = 0; | |
817 | out: | |
818 | return error; | |
819 | } | |
820 | ||
fadad878 | 821 | static int copy_io(unsigned long clone_flags, struct task_struct *tsk) |
fd0928df JA |
822 | { |
823 | #ifdef CONFIG_BLOCK | |
824 | struct io_context *ioc = current->io_context; | |
825 | ||
826 | if (!ioc) | |
827 | return 0; | |
fadad878 JA |
828 | /* |
829 | * Share io context with parent, if CLONE_IO is set | |
830 | */ | |
831 | if (clone_flags & CLONE_IO) { | |
832 | tsk->io_context = ioc_task_link(ioc); | |
833 | if (unlikely(!tsk->io_context)) | |
834 | return -ENOMEM; | |
835 | } else if (ioprio_valid(ioc->ioprio)) { | |
fd0928df JA |
836 | tsk->io_context = alloc_io_context(GFP_KERNEL, -1); |
837 | if (unlikely(!tsk->io_context)) | |
838 | return -ENOMEM; | |
839 | ||
fd0928df JA |
840 | tsk->io_context->ioprio = ioc->ioprio; |
841 | } | |
842 | #endif | |
843 | return 0; | |
844 | } | |
845 | ||
a39bc516 | 846 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
847 | { |
848 | struct sighand_struct *sig; | |
849 | ||
60348802 | 850 | if (clone_flags & CLONE_SIGHAND) { |
1da177e4 LT |
851 | atomic_inc(¤t->sighand->count); |
852 | return 0; | |
853 | } | |
854 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
e56d0903 | 855 | rcu_assign_pointer(tsk->sighand, sig); |
1da177e4 LT |
856 | if (!sig) |
857 | return -ENOMEM; | |
1da177e4 LT |
858 | atomic_set(&sig->count, 1); |
859 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); | |
860 | return 0; | |
861 | } | |
862 | ||
a7e5328a | 863 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 864 | { |
c81addc9 ON |
865 | if (atomic_dec_and_test(&sighand->count)) |
866 | kmem_cache_free(sighand_cachep, sighand); | |
867 | } | |
868 | ||
f06febc9 FM |
869 | |
870 | /* | |
871 | * Initialize POSIX timer handling for a thread group. | |
872 | */ | |
873 | static void posix_cpu_timers_init_group(struct signal_struct *sig) | |
874 | { | |
78d7d407 JS |
875 | unsigned long cpu_limit; |
876 | ||
f06febc9 FM |
877 | /* Thread group counters. */ |
878 | thread_group_cputime_init(sig); | |
879 | ||
78d7d407 JS |
880 | cpu_limit = ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur); |
881 | if (cpu_limit != RLIM_INFINITY) { | |
882 | sig->cputime_expires.prof_exp = secs_to_cputime(cpu_limit); | |
6279a751 ON |
883 | sig->cputimer.running = 1; |
884 | } | |
885 | ||
f06febc9 FM |
886 | /* The timer lists. */ |
887 | INIT_LIST_HEAD(&sig->cpu_timers[0]); | |
888 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
889 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
890 | } | |
891 | ||
a39bc516 | 892 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
893 | { |
894 | struct signal_struct *sig; | |
1da177e4 | 895 | |
4ab6c083 | 896 | if (clone_flags & CLONE_THREAD) |
490dea45 | 897 | return 0; |
490dea45 | 898 | |
a56704ef | 899 | sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL); |
1da177e4 LT |
900 | tsk->signal = sig; |
901 | if (!sig) | |
902 | return -ENOMEM; | |
903 | ||
b3ac022c | 904 | sig->nr_threads = 1; |
1da177e4 | 905 | atomic_set(&sig->live, 1); |
b3ac022c | 906 | atomic_set(&sig->sigcnt, 1); |
1da177e4 | 907 | init_waitqueue_head(&sig->wait_chldexit); |
b3bfa0cb SB |
908 | if (clone_flags & CLONE_NEWPID) |
909 | sig->flags |= SIGNAL_UNKILLABLE; | |
db51aecc | 910 | sig->curr_target = tsk; |
1da177e4 LT |
911 | init_sigpending(&sig->shared_pending); |
912 | INIT_LIST_HEAD(&sig->posix_timers); | |
913 | ||
c9cb2e3d | 914 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
1da177e4 | 915 | sig->real_timer.function = it_real_fn; |
1da177e4 | 916 | |
1da177e4 LT |
917 | task_lock(current->group_leader); |
918 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
919 | task_unlock(current->group_leader); | |
920 | ||
6279a751 ON |
921 | posix_cpu_timers_init_group(sig); |
922 | ||
522ed776 | 923 | tty_audit_fork(sig); |
5091faa4 | 924 | sched_autogroup_fork(sig); |
522ed776 | 925 | |
28b83c51 | 926 | sig->oom_adj = current->signal->oom_adj; |
a63d83f4 | 927 | sig->oom_score_adj = current->signal->oom_score_adj; |
dabb16f6 | 928 | sig->oom_score_adj_min = current->signal->oom_score_adj_min; |
28b83c51 | 929 | |
9b1bf12d KM |
930 | mutex_init(&sig->cred_guard_mutex); |
931 | ||
1da177e4 LT |
932 | return 0; |
933 | } | |
934 | ||
a39bc516 | 935 | static void copy_flags(unsigned long clone_flags, struct task_struct *p) |
1da177e4 LT |
936 | { |
937 | unsigned long new_flags = p->flags; | |
938 | ||
21aa9af0 | 939 | new_flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER); |
1da177e4 | 940 | new_flags |= PF_FORKNOEXEC; |
09a05394 | 941 | new_flags |= PF_STARTING; |
1da177e4 | 942 | p->flags = new_flags; |
2e131895 | 943 | clear_freeze_flag(p); |
1da177e4 LT |
944 | } |
945 | ||
17da2bd9 | 946 | SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr) |
1da177e4 LT |
947 | { |
948 | current->clear_child_tid = tidptr; | |
949 | ||
b488893a | 950 | return task_pid_vnr(current); |
1da177e4 LT |
951 | } |
952 | ||
a39bc516 | 953 | static void rt_mutex_init_task(struct task_struct *p) |
23f78d4a | 954 | { |
1d615482 | 955 | raw_spin_lock_init(&p->pi_lock); |
e29e175b | 956 | #ifdef CONFIG_RT_MUTEXES |
1d615482 | 957 | plist_head_init_raw(&p->pi_waiters, &p->pi_lock); |
23f78d4a | 958 | p->pi_blocked_on = NULL; |
23f78d4a IM |
959 | #endif |
960 | } | |
961 | ||
cf475ad2 BS |
962 | #ifdef CONFIG_MM_OWNER |
963 | void mm_init_owner(struct mm_struct *mm, struct task_struct *p) | |
964 | { | |
965 | mm->owner = p; | |
966 | } | |
967 | #endif /* CONFIG_MM_OWNER */ | |
968 | ||
f06febc9 FM |
969 | /* |
970 | * Initialize POSIX timer handling for a single task. | |
971 | */ | |
972 | static void posix_cpu_timers_init(struct task_struct *tsk) | |
973 | { | |
974 | tsk->cputime_expires.prof_exp = cputime_zero; | |
975 | tsk->cputime_expires.virt_exp = cputime_zero; | |
976 | tsk->cputime_expires.sched_exp = 0; | |
977 | INIT_LIST_HEAD(&tsk->cpu_timers[0]); | |
978 | INIT_LIST_HEAD(&tsk->cpu_timers[1]); | |
979 | INIT_LIST_HEAD(&tsk->cpu_timers[2]); | |
980 | } | |
981 | ||
1da177e4 LT |
982 | /* |
983 | * This creates a new process as a copy of the old one, | |
984 | * but does not actually start it yet. | |
985 | * | |
986 | * It copies the registers, and all the appropriate | |
987 | * parts of the process environment (as per the clone | |
988 | * flags). The actual kick-off is left to the caller. | |
989 | */ | |
36c8b586 IM |
990 | static struct task_struct *copy_process(unsigned long clone_flags, |
991 | unsigned long stack_start, | |
992 | struct pt_regs *regs, | |
993 | unsigned long stack_size, | |
36c8b586 | 994 | int __user *child_tidptr, |
09a05394 RM |
995 | struct pid *pid, |
996 | int trace) | |
1da177e4 LT |
997 | { |
998 | int retval; | |
a24efe62 | 999 | struct task_struct *p; |
b4f48b63 | 1000 | int cgroup_callbacks_done = 0; |
1da177e4 LT |
1001 | |
1002 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) | |
1003 | return ERR_PTR(-EINVAL); | |
1004 | ||
1005 | /* | |
1006 | * Thread groups must share signals as well, and detached threads | |
1007 | * can only be started up within the thread group. | |
1008 | */ | |
1009 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
1010 | return ERR_PTR(-EINVAL); | |
1011 | ||
1012 | /* | |
1013 | * Shared signal handlers imply shared VM. By way of the above, | |
1014 | * thread groups also imply shared VM. Blocking this case allows | |
1015 | * for various simplifications in other code. | |
1016 | */ | |
1017 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
1018 | return ERR_PTR(-EINVAL); | |
1019 | ||
123be07b SB |
1020 | /* |
1021 | * Siblings of global init remain as zombies on exit since they are | |
1022 | * not reaped by their parent (swapper). To solve this and to avoid | |
1023 | * multi-rooted process trees, prevent global and container-inits | |
1024 | * from creating siblings. | |
1025 | */ | |
1026 | if ((clone_flags & CLONE_PARENT) && | |
1027 | current->signal->flags & SIGNAL_UNKILLABLE) | |
1028 | return ERR_PTR(-EINVAL); | |
1029 | ||
1da177e4 LT |
1030 | retval = security_task_create(clone_flags); |
1031 | if (retval) | |
1032 | goto fork_out; | |
1033 | ||
1034 | retval = -ENOMEM; | |
1035 | p = dup_task_struct(current); | |
1036 | if (!p) | |
1037 | goto fork_out; | |
1038 | ||
f7e8b616 SR |
1039 | ftrace_graph_init_task(p); |
1040 | ||
bea493a0 PZ |
1041 | rt_mutex_init_task(p); |
1042 | ||
d12c1a37 | 1043 | #ifdef CONFIG_PROVE_LOCKING |
de30a2b3 IM |
1044 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); |
1045 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); | |
1046 | #endif | |
1da177e4 | 1047 | retval = -EAGAIN; |
3b11a1de | 1048 | if (atomic_read(&p->real_cred->user->processes) >= |
78d7d407 | 1049 | task_rlimit(p, RLIMIT_NPROC)) { |
1da177e4 | 1050 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) && |
18b6e041 | 1051 | p->real_cred->user != INIT_USER) |
1da177e4 LT |
1052 | goto bad_fork_free; |
1053 | } | |
1054 | ||
f1752eec DH |
1055 | retval = copy_creds(p, clone_flags); |
1056 | if (retval < 0) | |
1057 | goto bad_fork_free; | |
1da177e4 LT |
1058 | |
1059 | /* | |
1060 | * If multiple threads are within copy_process(), then this check | |
1061 | * triggers too late. This doesn't hurt, the check is only there | |
1062 | * to stop root fork bombs. | |
1063 | */ | |
04ec93fe | 1064 | retval = -EAGAIN; |
1da177e4 LT |
1065 | if (nr_threads >= max_threads) |
1066 | goto bad_fork_cleanup_count; | |
1067 | ||
a1261f54 | 1068 | if (!try_module_get(task_thread_info(p)->exec_domain->module)) |
1da177e4 LT |
1069 | goto bad_fork_cleanup_count; |
1070 | ||
1da177e4 | 1071 | p->did_exec = 0; |
ca74e92b | 1072 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
1da177e4 | 1073 | copy_flags(clone_flags, p); |
1da177e4 LT |
1074 | INIT_LIST_HEAD(&p->children); |
1075 | INIT_LIST_HEAD(&p->sibling); | |
f41d911f | 1076 | rcu_copy_process(p); |
1da177e4 LT |
1077 | p->vfork_done = NULL; |
1078 | spin_lock_init(&p->alloc_lock); | |
1da177e4 | 1079 | |
1da177e4 LT |
1080 | init_sigpending(&p->pending); |
1081 | ||
1082 | p->utime = cputime_zero; | |
1083 | p->stime = cputime_zero; | |
9ac52315 | 1084 | p->gtime = cputime_zero; |
c66f08be MN |
1085 | p->utimescaled = cputime_zero; |
1086 | p->stimescaled = cputime_zero; | |
d99ca3b9 | 1087 | #ifndef CONFIG_VIRT_CPU_ACCOUNTING |
73a2bcb0 | 1088 | p->prev_utime = cputime_zero; |
9301899b | 1089 | p->prev_stime = cputime_zero; |
d99ca3b9 | 1090 | #endif |
a3a2e76c KH |
1091 | #if defined(SPLIT_RSS_COUNTING) |
1092 | memset(&p->rss_stat, 0, sizeof(p->rss_stat)); | |
1093 | #endif | |
172ba844 | 1094 | |
6976675d AV |
1095 | p->default_timer_slack_ns = current->timer_slack_ns; |
1096 | ||
5995477a | 1097 | task_io_accounting_init(&p->ioac); |
1da177e4 LT |
1098 | acct_clear_integrals(p); |
1099 | ||
f06febc9 | 1100 | posix_cpu_timers_init(p); |
1da177e4 LT |
1101 | |
1102 | p->lock_depth = -1; /* -1 = no lock */ | |
1103 | do_posix_clock_monotonic_gettime(&p->start_time); | |
924b42d5 TJ |
1104 | p->real_start_time = p->start_time; |
1105 | monotonic_to_bootbased(&p->real_start_time); | |
1da177e4 | 1106 | p->io_context = NULL; |
1da177e4 | 1107 | p->audit_context = NULL; |
b4f48b63 | 1108 | cgroup_fork(p); |
1da177e4 | 1109 | #ifdef CONFIG_NUMA |
846a16bf | 1110 | p->mempolicy = mpol_dup(p->mempolicy); |
1da177e4 LT |
1111 | if (IS_ERR(p->mempolicy)) { |
1112 | retval = PTR_ERR(p->mempolicy); | |
1113 | p->mempolicy = NULL; | |
b4f48b63 | 1114 | goto bad_fork_cleanup_cgroup; |
1da177e4 | 1115 | } |
c61afb18 | 1116 | mpol_fix_fork_child_flag(p); |
1da177e4 | 1117 | #endif |
de30a2b3 IM |
1118 | #ifdef CONFIG_TRACE_IRQFLAGS |
1119 | p->irq_events = 0; | |
b36e4758 RK |
1120 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
1121 | p->hardirqs_enabled = 1; | |
1122 | #else | |
de30a2b3 | 1123 | p->hardirqs_enabled = 0; |
b36e4758 | 1124 | #endif |
de30a2b3 IM |
1125 | p->hardirq_enable_ip = 0; |
1126 | p->hardirq_enable_event = 0; | |
1127 | p->hardirq_disable_ip = _THIS_IP_; | |
1128 | p->hardirq_disable_event = 0; | |
1129 | p->softirqs_enabled = 1; | |
1130 | p->softirq_enable_ip = _THIS_IP_; | |
1131 | p->softirq_enable_event = 0; | |
1132 | p->softirq_disable_ip = 0; | |
1133 | p->softirq_disable_event = 0; | |
1134 | p->hardirq_context = 0; | |
1135 | p->softirq_context = 0; | |
1136 | #endif | |
fbb9ce95 IM |
1137 | #ifdef CONFIG_LOCKDEP |
1138 | p->lockdep_depth = 0; /* no locks held yet */ | |
1139 | p->curr_chain_key = 0; | |
1140 | p->lockdep_recursion = 0; | |
1141 | #endif | |
1da177e4 | 1142 | |
408894ee IM |
1143 | #ifdef CONFIG_DEBUG_MUTEXES |
1144 | p->blocked_on = NULL; /* not blocked yet */ | |
1145 | #endif | |
569b846d KH |
1146 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
1147 | p->memcg_batch.do_batch = 0; | |
1148 | p->memcg_batch.memcg = NULL; | |
1149 | #endif | |
0f481406 | 1150 | |
3c90e6e9 SV |
1151 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
1152 | sched_fork(p, clone_flags); | |
6ab423e0 | 1153 | |
cdd6c482 | 1154 | retval = perf_event_init_task(p); |
6ab423e0 PZ |
1155 | if (retval) |
1156 | goto bad_fork_cleanup_policy; | |
3c90e6e9 | 1157 | |
1da177e4 | 1158 | if ((retval = audit_alloc(p))) |
f1752eec | 1159 | goto bad_fork_cleanup_policy; |
1da177e4 LT |
1160 | /* copy all the process information */ |
1161 | if ((retval = copy_semundo(clone_flags, p))) | |
1162 | goto bad_fork_cleanup_audit; | |
1163 | if ((retval = copy_files(clone_flags, p))) | |
1164 | goto bad_fork_cleanup_semundo; | |
1165 | if ((retval = copy_fs(clone_flags, p))) | |
1166 | goto bad_fork_cleanup_files; | |
1167 | if ((retval = copy_sighand(clone_flags, p))) | |
1168 | goto bad_fork_cleanup_fs; | |
1169 | if ((retval = copy_signal(clone_flags, p))) | |
1170 | goto bad_fork_cleanup_sighand; | |
1171 | if ((retval = copy_mm(clone_flags, p))) | |
1172 | goto bad_fork_cleanup_signal; | |
ab516013 | 1173 | if ((retval = copy_namespaces(clone_flags, p))) |
d84f4f99 | 1174 | goto bad_fork_cleanup_mm; |
fadad878 | 1175 | if ((retval = copy_io(clone_flags, p))) |
fd0928df | 1176 | goto bad_fork_cleanup_namespaces; |
6f2c55b8 | 1177 | retval = copy_thread(clone_flags, stack_start, stack_size, p, regs); |
1da177e4 | 1178 | if (retval) |
fd0928df | 1179 | goto bad_fork_cleanup_io; |
1da177e4 | 1180 | |
425fb2b4 PE |
1181 | if (pid != &init_struct_pid) { |
1182 | retval = -ENOMEM; | |
61bce0f1 | 1183 | pid = alloc_pid(p->nsproxy->pid_ns); |
425fb2b4 | 1184 | if (!pid) |
fd0928df | 1185 | goto bad_fork_cleanup_io; |
6f4e6433 PE |
1186 | |
1187 | if (clone_flags & CLONE_NEWPID) { | |
61bce0f1 | 1188 | retval = pid_ns_prepare_proc(p->nsproxy->pid_ns); |
6f4e6433 PE |
1189 | if (retval < 0) |
1190 | goto bad_fork_free_pid; | |
1191 | } | |
425fb2b4 PE |
1192 | } |
1193 | ||
1194 | p->pid = pid_nr(pid); | |
1195 | p->tgid = p->pid; | |
1196 | if (clone_flags & CLONE_THREAD) | |
1197 | p->tgid = current->tgid; | |
1198 | ||
e885dcde SH |
1199 | if (current->nsproxy != p->nsproxy) { |
1200 | retval = ns_cgroup_clone(p, pid); | |
1201 | if (retval) | |
f7e8b616 | 1202 | goto bad_fork_free_pid; |
e885dcde SH |
1203 | } |
1204 | ||
1da177e4 LT |
1205 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; |
1206 | /* | |
1207 | * Clear TID on mm_release()? | |
1208 | */ | |
1209 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL; | |
42b2dd0a | 1210 | #ifdef CONFIG_FUTEX |
8f17d3a5 IM |
1211 | p->robust_list = NULL; |
1212 | #ifdef CONFIG_COMPAT | |
1213 | p->compat_robust_list = NULL; | |
1214 | #endif | |
c87e2837 IM |
1215 | INIT_LIST_HEAD(&p->pi_state_list); |
1216 | p->pi_state_cache = NULL; | |
42b2dd0a | 1217 | #endif |
f9a3879a GM |
1218 | /* |
1219 | * sigaltstack should be cleared when sharing the same VM | |
1220 | */ | |
1221 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
1222 | p->sas_ss_sp = p->sas_ss_size = 0; | |
1223 | ||
1da177e4 | 1224 | /* |
6580807d ON |
1225 | * Syscall tracing and stepping should be turned off in the |
1226 | * child regardless of CLONE_PTRACE. | |
1da177e4 | 1227 | */ |
6580807d | 1228 | user_disable_single_step(p); |
1da177e4 | 1229 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); |
ed75e8d5 LV |
1230 | #ifdef TIF_SYSCALL_EMU |
1231 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1232 | #endif | |
9745512c | 1233 | clear_all_latency_tracing(p); |
1da177e4 | 1234 | |
1da177e4 LT |
1235 | /* ok, now we should be set up.. */ |
1236 | p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL); | |
1237 | p->pdeath_signal = 0; | |
1238 | p->exit_state = 0; | |
1239 | ||
1da177e4 LT |
1240 | /* |
1241 | * Ok, make it visible to the rest of the system. | |
1242 | * We dont wake it up yet. | |
1243 | */ | |
1244 | p->group_leader = p; | |
47e65328 | 1245 | INIT_LIST_HEAD(&p->thread_group); |
1da177e4 | 1246 | |
b4f48b63 PM |
1247 | /* Now that the task is set up, run cgroup callbacks if |
1248 | * necessary. We need to run them before the task is visible | |
1249 | * on the tasklist. */ | |
1250 | cgroup_fork_callbacks(p); | |
1251 | cgroup_callbacks_done = 1; | |
1252 | ||
1da177e4 LT |
1253 | /* Need tasklist lock for parent etc handling! */ |
1254 | write_lock_irq(&tasklist_lock); | |
1255 | ||
1da177e4 | 1256 | /* CLONE_PARENT re-uses the old parent */ |
2d5516cb | 1257 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) { |
1da177e4 | 1258 | p->real_parent = current->real_parent; |
2d5516cb ON |
1259 | p->parent_exec_id = current->parent_exec_id; |
1260 | } else { | |
1da177e4 | 1261 | p->real_parent = current; |
2d5516cb ON |
1262 | p->parent_exec_id = current->self_exec_id; |
1263 | } | |
1da177e4 | 1264 | |
3f17da69 | 1265 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 ON |
1266 | |
1267 | /* | |
1268 | * Process group and session signals need to be delivered to just the | |
1269 | * parent before the fork or both the parent and the child after the | |
1270 | * fork. Restart if a signal comes in before we add the new process to | |
1271 | * it's process group. | |
1272 | * A fatal signal pending means that current will exit, so the new | |
1273 | * thread can't slip out of an OOM kill (or normal SIGKILL). | |
1274 | */ | |
23ff4440 | 1275 | recalc_sigpending(); |
4a2c7a78 ON |
1276 | if (signal_pending(current)) { |
1277 | spin_unlock(¤t->sighand->siglock); | |
1278 | write_unlock_irq(&tasklist_lock); | |
1279 | retval = -ERESTARTNOINTR; | |
f7e8b616 | 1280 | goto bad_fork_free_pid; |
4a2c7a78 ON |
1281 | } |
1282 | ||
1da177e4 | 1283 | if (clone_flags & CLONE_THREAD) { |
b3ac022c | 1284 | current->signal->nr_threads++; |
4ab6c083 | 1285 | atomic_inc(¤t->signal->live); |
b3ac022c | 1286 | atomic_inc(¤t->signal->sigcnt); |
1da177e4 | 1287 | p->group_leader = current->group_leader; |
47e65328 | 1288 | list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); |
1da177e4 LT |
1289 | } |
1290 | ||
73b9ebfe | 1291 | if (likely(p->pid)) { |
09a05394 | 1292 | tracehook_finish_clone(p, clone_flags, trace); |
73b9ebfe ON |
1293 | |
1294 | if (thread_group_leader(p)) { | |
5cd17569 | 1295 | if (clone_flags & CLONE_NEWPID) |
30e49c26 | 1296 | p->nsproxy->pid_ns->child_reaper = p; |
73b9ebfe | 1297 | |
fea9d175 | 1298 | p->signal->leader_pid = pid; |
9c9f4ded | 1299 | p->signal->tty = tty_kref_get(current->signal->tty); |
5cd17569 EB |
1300 | attach_pid(p, PIDTYPE_PGID, task_pgrp(current)); |
1301 | attach_pid(p, PIDTYPE_SID, task_session(current)); | |
9cd80bbb | 1302 | list_add_tail(&p->sibling, &p->real_parent->children); |
5e85d4ab | 1303 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
909ea964 | 1304 | __this_cpu_inc(process_counts); |
73b9ebfe | 1305 | } |
85868995 | 1306 | attach_pid(p, PIDTYPE_PID, pid); |
73b9ebfe | 1307 | nr_threads++; |
1da177e4 LT |
1308 | } |
1309 | ||
1da177e4 | 1310 | total_forks++; |
3f17da69 | 1311 | spin_unlock(¤t->sighand->siglock); |
1da177e4 | 1312 | write_unlock_irq(&tasklist_lock); |
c13cf856 | 1313 | proc_fork_connector(p); |
817929ec | 1314 | cgroup_post_fork(p); |
cdd6c482 | 1315 | perf_event_fork(p); |
1da177e4 LT |
1316 | return p; |
1317 | ||
425fb2b4 PE |
1318 | bad_fork_free_pid: |
1319 | if (pid != &init_struct_pid) | |
1320 | free_pid(pid); | |
fd0928df | 1321 | bad_fork_cleanup_io: |
b69f2292 LR |
1322 | if (p->io_context) |
1323 | exit_io_context(p); | |
ab516013 | 1324 | bad_fork_cleanup_namespaces: |
444f378b | 1325 | exit_task_namespaces(p); |
1da177e4 | 1326 | bad_fork_cleanup_mm: |
3d5992d2 YH |
1327 | if (p->mm) { |
1328 | task_lock(p); | |
1329 | if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) | |
1330 | atomic_dec(&p->mm->oom_disable_count); | |
1331 | task_unlock(p); | |
1da177e4 | 1332 | mmput(p->mm); |
3d5992d2 | 1333 | } |
1da177e4 | 1334 | bad_fork_cleanup_signal: |
4ab6c083 | 1335 | if (!(clone_flags & CLONE_THREAD)) |
1c5354de | 1336 | free_signal_struct(p->signal); |
1da177e4 | 1337 | bad_fork_cleanup_sighand: |
a7e5328a | 1338 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
1339 | bad_fork_cleanup_fs: |
1340 | exit_fs(p); /* blocking */ | |
1341 | bad_fork_cleanup_files: | |
1342 | exit_files(p); /* blocking */ | |
1343 | bad_fork_cleanup_semundo: | |
1344 | exit_sem(p); | |
1345 | bad_fork_cleanup_audit: | |
1346 | audit_free(p); | |
1da177e4 | 1347 | bad_fork_cleanup_policy: |
cdd6c482 | 1348 | perf_event_free_task(p); |
1da177e4 | 1349 | #ifdef CONFIG_NUMA |
f0be3d32 | 1350 | mpol_put(p->mempolicy); |
b4f48b63 | 1351 | bad_fork_cleanup_cgroup: |
1da177e4 | 1352 | #endif |
b4f48b63 | 1353 | cgroup_exit(p, cgroup_callbacks_done); |
35df17c5 | 1354 | delayacct_tsk_free(p); |
a1261f54 | 1355 | module_put(task_thread_info(p)->exec_domain->module); |
1da177e4 | 1356 | bad_fork_cleanup_count: |
d84f4f99 | 1357 | atomic_dec(&p->cred->user->processes); |
e0e81739 | 1358 | exit_creds(p); |
1da177e4 LT |
1359 | bad_fork_free: |
1360 | free_task(p); | |
fe7d37d1 ON |
1361 | fork_out: |
1362 | return ERR_PTR(retval); | |
1da177e4 LT |
1363 | } |
1364 | ||
6b2fb3c6 | 1365 | noinline struct pt_regs * __cpuinit __attribute__((weak)) idle_regs(struct pt_regs *regs) |
1da177e4 LT |
1366 | { |
1367 | memset(regs, 0, sizeof(struct pt_regs)); | |
1368 | return regs; | |
1369 | } | |
1370 | ||
f106eee1 ON |
1371 | static inline void init_idle_pids(struct pid_link *links) |
1372 | { | |
1373 | enum pid_type type; | |
1374 | ||
1375 | for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) { | |
1376 | INIT_HLIST_NODE(&links[type].node); /* not really needed */ | |
1377 | links[type].pid = &init_struct_pid; | |
1378 | } | |
1379 | } | |
1380 | ||
9abcf40b | 1381 | struct task_struct * __cpuinit fork_idle(int cpu) |
1da177e4 | 1382 | { |
36c8b586 | 1383 | struct task_struct *task; |
1da177e4 LT |
1384 | struct pt_regs regs; |
1385 | ||
30e49c26 | 1386 | task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, |
09a05394 | 1387 | &init_struct_pid, 0); |
f106eee1 ON |
1388 | if (!IS_ERR(task)) { |
1389 | init_idle_pids(task->pids); | |
753ca4f3 | 1390 | init_idle(task, cpu); |
f106eee1 | 1391 | } |
73b9ebfe | 1392 | |
1da177e4 LT |
1393 | return task; |
1394 | } | |
1395 | ||
1da177e4 LT |
1396 | /* |
1397 | * Ok, this is the main fork-routine. | |
1398 | * | |
1399 | * It copies the process, and if successful kick-starts | |
1400 | * it and waits for it to finish using the VM if required. | |
1401 | */ | |
1402 | long do_fork(unsigned long clone_flags, | |
1403 | unsigned long stack_start, | |
1404 | struct pt_regs *regs, | |
1405 | unsigned long stack_size, | |
1406 | int __user *parent_tidptr, | |
1407 | int __user *child_tidptr) | |
1408 | { | |
1409 | struct task_struct *p; | |
1410 | int trace = 0; | |
92476d7f | 1411 | long nr; |
1da177e4 | 1412 | |
18b6e041 SH |
1413 | /* |
1414 | * Do some preliminary argument and permissions checking before we | |
1415 | * actually start allocating stuff | |
1416 | */ | |
1417 | if (clone_flags & CLONE_NEWUSER) { | |
1418 | if (clone_flags & CLONE_THREAD) | |
1419 | return -EINVAL; | |
1420 | /* hopefully this check will go away when userns support is | |
1421 | * complete | |
1422 | */ | |
7657d904 SH |
1423 | if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SETUID) || |
1424 | !capable(CAP_SETGID)) | |
18b6e041 SH |
1425 | return -EPERM; |
1426 | } | |
1427 | ||
09a05394 RM |
1428 | /* |
1429 | * When called from kernel_thread, don't do user tracing stuff. | |
1430 | */ | |
1431 | if (likely(user_mode(regs))) | |
1432 | trace = tracehook_prepare_clone(clone_flags); | |
1da177e4 | 1433 | |
a6f5e063 | 1434 | p = copy_process(clone_flags, stack_start, regs, stack_size, |
09a05394 | 1435 | child_tidptr, NULL, trace); |
1da177e4 LT |
1436 | /* |
1437 | * Do this prior waking up the new thread - the thread pointer | |
1438 | * might get invalid after that point, if the thread exits quickly. | |
1439 | */ | |
1440 | if (!IS_ERR(p)) { | |
1441 | struct completion vfork; | |
1442 | ||
0a16b607 MD |
1443 | trace_sched_process_fork(current, p); |
1444 | ||
6c5f3e7b | 1445 | nr = task_pid_vnr(p); |
30e49c26 PE |
1446 | |
1447 | if (clone_flags & CLONE_PARENT_SETTID) | |
1448 | put_user(nr, parent_tidptr); | |
a6f5e063 | 1449 | |
1da177e4 LT |
1450 | if (clone_flags & CLONE_VFORK) { |
1451 | p->vfork_done = &vfork; | |
1452 | init_completion(&vfork); | |
1453 | } | |
1454 | ||
a64e6494 | 1455 | audit_finish_fork(p); |
087eb437 | 1456 | tracehook_report_clone(regs, clone_flags, nr, p); |
09a05394 RM |
1457 | |
1458 | /* | |
1459 | * We set PF_STARTING at creation in case tracing wants to | |
1460 | * use this to distinguish a fully live task from one that | |
1461 | * hasn't gotten to tracehook_report_clone() yet. Now we | |
1462 | * clear it and set the child going. | |
1463 | */ | |
1464 | p->flags &= ~PF_STARTING; | |
1465 | ||
43bb40c9 | 1466 | wake_up_new_task(p, clone_flags); |
1da177e4 | 1467 | |
09a05394 RM |
1468 | tracehook_report_clone_complete(trace, regs, |
1469 | clone_flags, nr, p); | |
1470 | ||
1da177e4 | 1471 | if (clone_flags & CLONE_VFORK) { |
ba96a0c8 | 1472 | freezer_do_not_count(); |
1da177e4 | 1473 | wait_for_completion(&vfork); |
ba96a0c8 | 1474 | freezer_count(); |
daded34b | 1475 | tracehook_report_vfork_done(p, nr); |
1da177e4 LT |
1476 | } |
1477 | } else { | |
92476d7f | 1478 | nr = PTR_ERR(p); |
1da177e4 | 1479 | } |
92476d7f | 1480 | return nr; |
1da177e4 LT |
1481 | } |
1482 | ||
5fd63b30 RT |
1483 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
1484 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
1485 | #endif | |
1486 | ||
51cc5068 | 1487 | static void sighand_ctor(void *data) |
aa1757f9 ON |
1488 | { |
1489 | struct sighand_struct *sighand = data; | |
1490 | ||
a35afb83 | 1491 | spin_lock_init(&sighand->siglock); |
b8fceee1 | 1492 | init_waitqueue_head(&sighand->signalfd_wqh); |
aa1757f9 ON |
1493 | } |
1494 | ||
1da177e4 LT |
1495 | void __init proc_caches_init(void) |
1496 | { | |
1497 | sighand_cachep = kmem_cache_create("sighand_cache", | |
1498 | sizeof(struct sighand_struct), 0, | |
2dff4405 VN |
1499 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU| |
1500 | SLAB_NOTRACK, sighand_ctor); | |
1da177e4 LT |
1501 | signal_cachep = kmem_cache_create("signal_cache", |
1502 | sizeof(struct signal_struct), 0, | |
2dff4405 | 1503 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
20c2df83 | 1504 | files_cachep = kmem_cache_create("files_cache", |
1da177e4 | 1505 | sizeof(struct files_struct), 0, |
2dff4405 | 1506 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
20c2df83 | 1507 | fs_cachep = kmem_cache_create("fs_cache", |
1da177e4 | 1508 | sizeof(struct fs_struct), 0, |
2dff4405 | 1509 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
1da177e4 | 1510 | mm_cachep = kmem_cache_create("mm_struct", |
5fd63b30 | 1511 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
2dff4405 | 1512 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
33e5d769 | 1513 | vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC); |
8feae131 | 1514 | mmap_init(); |
1da177e4 | 1515 | } |
cf2e340f | 1516 | |
cf2e340f JD |
1517 | /* |
1518 | * Check constraints on flags passed to the unshare system call and | |
1519 | * force unsharing of additional process context as appropriate. | |
1520 | */ | |
a39bc516 | 1521 | static void check_unshare_flags(unsigned long *flags_ptr) |
cf2e340f JD |
1522 | { |
1523 | /* | |
1524 | * If unsharing a thread from a thread group, must also | |
1525 | * unshare vm. | |
1526 | */ | |
1527 | if (*flags_ptr & CLONE_THREAD) | |
1528 | *flags_ptr |= CLONE_VM; | |
1529 | ||
1530 | /* | |
1531 | * If unsharing vm, must also unshare signal handlers. | |
1532 | */ | |
1533 | if (*flags_ptr & CLONE_VM) | |
1534 | *flags_ptr |= CLONE_SIGHAND; | |
1535 | ||
cf2e340f JD |
1536 | /* |
1537 | * If unsharing namespace, must also unshare filesystem information. | |
1538 | */ | |
1539 | if (*flags_ptr & CLONE_NEWNS) | |
1540 | *flags_ptr |= CLONE_FS; | |
1541 | } | |
1542 | ||
1543 | /* | |
1544 | * Unsharing of tasks created with CLONE_THREAD is not supported yet | |
1545 | */ | |
1546 | static int unshare_thread(unsigned long unshare_flags) | |
1547 | { | |
1548 | if (unshare_flags & CLONE_THREAD) | |
1549 | return -EINVAL; | |
1550 | ||
1551 | return 0; | |
1552 | } | |
1553 | ||
1554 | /* | |
99d1419d | 1555 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
1556 | */ |
1557 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
1558 | { | |
1559 | struct fs_struct *fs = current->fs; | |
1560 | ||
498052bb AV |
1561 | if (!(unshare_flags & CLONE_FS) || !fs) |
1562 | return 0; | |
1563 | ||
1564 | /* don't need lock here; in the worst case we'll do useless copy */ | |
1565 | if (fs->users == 1) | |
1566 | return 0; | |
1567 | ||
1568 | *new_fsp = copy_fs_struct(fs); | |
1569 | if (!*new_fsp) | |
1570 | return -ENOMEM; | |
cf2e340f JD |
1571 | |
1572 | return 0; | |
1573 | } | |
1574 | ||
cf2e340f | 1575 | /* |
dae3c5a0 | 1576 | * Unsharing of sighand is not supported yet |
cf2e340f JD |
1577 | */ |
1578 | static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp) | |
1579 | { | |
1580 | struct sighand_struct *sigh = current->sighand; | |
1581 | ||
dae3c5a0 | 1582 | if ((unshare_flags & CLONE_SIGHAND) && atomic_read(&sigh->count) > 1) |
cf2e340f JD |
1583 | return -EINVAL; |
1584 | else | |
1585 | return 0; | |
1586 | } | |
1587 | ||
1588 | /* | |
a0a7ec30 | 1589 | * Unshare vm if it is being shared |
cf2e340f JD |
1590 | */ |
1591 | static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp) | |
1592 | { | |
1593 | struct mm_struct *mm = current->mm; | |
1594 | ||
1595 | if ((unshare_flags & CLONE_VM) && | |
a0a7ec30 | 1596 | (mm && atomic_read(&mm->mm_users) > 1)) { |
2d61b867 | 1597 | return -EINVAL; |
a0a7ec30 | 1598 | } |
cf2e340f JD |
1599 | |
1600 | return 0; | |
cf2e340f JD |
1601 | } |
1602 | ||
1603 | /* | |
a016f338 | 1604 | * Unshare file descriptor table if it is being shared |
cf2e340f JD |
1605 | */ |
1606 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) | |
1607 | { | |
1608 | struct files_struct *fd = current->files; | |
a016f338 | 1609 | int error = 0; |
cf2e340f JD |
1610 | |
1611 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 JD |
1612 | (fd && atomic_read(&fd->count) > 1)) { |
1613 | *new_fdp = dup_fd(fd, &error); | |
1614 | if (!*new_fdp) | |
1615 | return error; | |
1616 | } | |
cf2e340f JD |
1617 | |
1618 | return 0; | |
1619 | } | |
1620 | ||
cf2e340f JD |
1621 | /* |
1622 | * unshare allows a process to 'unshare' part of the process | |
1623 | * context which was originally shared using clone. copy_* | |
1624 | * functions used by do_fork() cannot be used here directly | |
1625 | * because they modify an inactive task_struct that is being | |
1626 | * constructed. Here we are modifying the current, active, | |
1627 | * task_struct. | |
1628 | */ | |
6559eed8 | 1629 | SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) |
cf2e340f JD |
1630 | { |
1631 | int err = 0; | |
1632 | struct fs_struct *fs, *new_fs = NULL; | |
dae3c5a0 | 1633 | struct sighand_struct *new_sigh = NULL; |
cf2e340f JD |
1634 | struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; |
1635 | struct files_struct *fd, *new_fd = NULL; | |
cf7b708c | 1636 | struct nsproxy *new_nsproxy = NULL; |
9edff4ab | 1637 | int do_sysvsem = 0; |
cf2e340f JD |
1638 | |
1639 | check_unshare_flags(&unshare_flags); | |
1640 | ||
06f9d4f9 EB |
1641 | /* Return -EINVAL for all unsupported flags */ |
1642 | err = -EINVAL; | |
1643 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| | |
25b21cb2 | 1644 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| |
18b6e041 | 1645 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET)) |
06f9d4f9 EB |
1646 | goto bad_unshare_out; |
1647 | ||
6013f67f MS |
1648 | /* |
1649 | * CLONE_NEWIPC must also detach from the undolist: after switching | |
1650 | * to a new ipc namespace, the semaphore arrays from the old | |
1651 | * namespace are unreachable. | |
1652 | */ | |
1653 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) | |
9edff4ab | 1654 | do_sysvsem = 1; |
cf2e340f JD |
1655 | if ((err = unshare_thread(unshare_flags))) |
1656 | goto bad_unshare_out; | |
1657 | if ((err = unshare_fs(unshare_flags, &new_fs))) | |
1658 | goto bad_unshare_cleanup_thread; | |
cf2e340f | 1659 | if ((err = unshare_sighand(unshare_flags, &new_sigh))) |
e3222c4e | 1660 | goto bad_unshare_cleanup_fs; |
cf2e340f JD |
1661 | if ((err = unshare_vm(unshare_flags, &new_mm))) |
1662 | goto bad_unshare_cleanup_sigh; | |
1663 | if ((err = unshare_fd(unshare_flags, &new_fd))) | |
1664 | goto bad_unshare_cleanup_vm; | |
e3222c4e BP |
1665 | if ((err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, |
1666 | new_fs))) | |
9edff4ab | 1667 | goto bad_unshare_cleanup_fd; |
c0b2fc31 | 1668 | |
9edff4ab MS |
1669 | if (new_fs || new_mm || new_fd || do_sysvsem || new_nsproxy) { |
1670 | if (do_sysvsem) { | |
1671 | /* | |
1672 | * CLONE_SYSVSEM is equivalent to sys_exit(). | |
1673 | */ | |
1674 | exit_sem(current); | |
1675 | } | |
ab516013 | 1676 | |
c0b2fc31 | 1677 | if (new_nsproxy) { |
cf7b708c PE |
1678 | switch_task_namespaces(current, new_nsproxy); |
1679 | new_nsproxy = NULL; | |
c0b2fc31 | 1680 | } |
cf2e340f | 1681 | |
cf7b708c PE |
1682 | task_lock(current); |
1683 | ||
cf2e340f JD |
1684 | if (new_fs) { |
1685 | fs = current->fs; | |
2a4419b5 | 1686 | spin_lock(&fs->lock); |
cf2e340f | 1687 | current->fs = new_fs; |
498052bb AV |
1688 | if (--fs->users) |
1689 | new_fs = NULL; | |
1690 | else | |
1691 | new_fs = fs; | |
2a4419b5 | 1692 | spin_unlock(&fs->lock); |
cf2e340f JD |
1693 | } |
1694 | ||
cf2e340f JD |
1695 | if (new_mm) { |
1696 | mm = current->mm; | |
1697 | active_mm = current->active_mm; | |
1698 | current->mm = new_mm; | |
1699 | current->active_mm = new_mm; | |
3d5992d2 YH |
1700 | if (current->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) { |
1701 | atomic_dec(&mm->oom_disable_count); | |
1702 | atomic_inc(&new_mm->oom_disable_count); | |
1703 | } | |
cf2e340f JD |
1704 | activate_mm(active_mm, new_mm); |
1705 | new_mm = mm; | |
1706 | } | |
1707 | ||
1708 | if (new_fd) { | |
1709 | fd = current->files; | |
1710 | current->files = new_fd; | |
1711 | new_fd = fd; | |
1712 | } | |
1713 | ||
1714 | task_unlock(current); | |
1715 | } | |
1716 | ||
c0b2fc31 | 1717 | if (new_nsproxy) |
444f378b | 1718 | put_nsproxy(new_nsproxy); |
c0b2fc31 | 1719 | |
cf2e340f JD |
1720 | bad_unshare_cleanup_fd: |
1721 | if (new_fd) | |
1722 | put_files_struct(new_fd); | |
1723 | ||
1724 | bad_unshare_cleanup_vm: | |
1725 | if (new_mm) | |
1726 | mmput(new_mm); | |
1727 | ||
1728 | bad_unshare_cleanup_sigh: | |
1729 | if (new_sigh) | |
1730 | if (atomic_dec_and_test(&new_sigh->count)) | |
1731 | kmem_cache_free(sighand_cachep, new_sigh); | |
1732 | ||
cf2e340f JD |
1733 | bad_unshare_cleanup_fs: |
1734 | if (new_fs) | |
498052bb | 1735 | free_fs_struct(new_fs); |
cf2e340f JD |
1736 | |
1737 | bad_unshare_cleanup_thread: | |
1738 | bad_unshare_out: | |
1739 | return err; | |
1740 | } | |
3b125388 AV |
1741 | |
1742 | /* | |
1743 | * Helper to unshare the files of the current task. | |
1744 | * We don't want to expose copy_files internals to | |
1745 | * the exec layer of the kernel. | |
1746 | */ | |
1747 | ||
1748 | int unshare_files(struct files_struct **displaced) | |
1749 | { | |
1750 | struct task_struct *task = current; | |
50704516 | 1751 | struct files_struct *copy = NULL; |
3b125388 AV |
1752 | int error; |
1753 | ||
1754 | error = unshare_fd(CLONE_FILES, ©); | |
1755 | if (error || !copy) { | |
1756 | *displaced = NULL; | |
1757 | return error; | |
1758 | } | |
1759 | *displaced = task->files; | |
1760 | task_lock(task); | |
1761 | task->files = copy; | |
1762 | task_unlock(task); | |
1763 | return 0; | |
1764 | } |